Plate heat exchanger with dual flow path

ABSTRACT

A plate heat exchanger includes a plurality of main plates stacked to define a first cavity to direct a first fluid therethrough and a second cavity to direct a second fluid therethrough, the second fluid different from and kept separated from the first fluid, and an intermediate plate located in the second cavity between adjacent main plates, the second fluid directed across both sides of the intermediate plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of 62/426,721, filed Nov. 28, 2016, which is incorporated herein by reference in its entirety.

BACKGROUND

Embodiments of this disclosure relate generally to heat exchangers. More specifically, the present disclosure relates to plate heat exchangers.

Plate Heat Exchangers (PHEs) and Brazed Plate Heat Exchangers (BPHEs) are formed of a series of plates that are stacked and sealed/brazed to form separate flow paths for two fluids. In many such PHEs and BPHEs, the fluids are typically refrigerant circulated through a first flow path and water or brine circulated through a second flowpath, with the PHE or BPHE facilitating thermal energy exchange between the two fluids. PHEs and BPHEs are utilized in, for example, commercial or residential chillers.

SUMMARY

In one embodiment, a plate heat exchanger includes a plurality of main plates stacked to define a first cavity to direct a first fluid therethrough and a second cavity to direct a second fluid therethrough, the second fluid different from and kept separated from the first fluid, and an intermediate plate located in the second cavity between adjacent main plates, the second fluid directed across both sides of the intermediate plate.

Additionally or alternatively, in this or other embodiments one or more surface enhancements are located at the intermediate plate to induce vortices in the second fluid.

Additionally or alternatively, in this or other embodiments the one or more surface enhancements are one or more of material deformation at the intermediate plate or material removal from the intermediate plate.

Additionally or alternatively, in this or other embodiments the main plates include a plurality of ridges and troughs, defining at least one main plate peak and at least one main plate valley.

Additionally or alternatively, in this or other embodiments the intermediate plate includes a plurality of ridges and troughs, defining at least one intermediate plate peak and at least one intermediate plate valley.

Additionally or alternatively, in this or other embodiments a pitch between adjacent intermediate plate peaks differs from a pitch between adjacent main plate peaks.

Additionally or alternatively, in this or other embodiments the pitch between adjacent intermediate plate peaks is greater than a pitch between adjacent main plate peaks.

Additionally or alternatively, in this or other embodiments the pitch between adjacent intermediate plate peaks is greater than a pitch between adjacent main plate peaks.

Additionally or alternatively, in this or other embodiments an amplitude between adjacent intermediate plate peaks and intermediate plate valleys differs from an amplitude between adjacent main plate peaks and main plate valleys.

Additionally or alternatively, in this or other embodiments the amplitude between adjacent intermediate plate peaks and intermediate plate valleys is greater than an amplitude between adjacent main plate peaks and main plate valleys.

Additionally or alternatively, in this or other embodiments the amplitude between adjacent intermediate plate peaks and intermediate plate valleys is less than an amplitude between adjacent main plate peaks and main plate valleys.

Additionally or alternatively, in this or other embodiments a second intermediate plate is located in the first cavity.

Additionally or alternatively, in this or other embodiments a first flow direction of the second fluid at a first side of the intermediate plate is the same as a second flow direction of the second fluid at a second side of the intermediate plate.

Additionally or alternatively, in this or other embodiments a first flow direction of the second fluid at a first side of the intermediate plate is different from a second flow direction of the second fluid at a second side of the intermediate plate.

In another embodiment, a plate heat exchanger includes a plurality of main plates stacked to define a first cavity to direct a first fluid therethrough and a second cavity to direct a second fluid therethrough, the second fluid different from and kept separated from the first fluid. Each main plate of the plurality of main plates includes a plurality of ridges and troughs, defining at least one main plate peak and at least one main plate valley. An intermediate plate is located in the second cavity between adjacent main plates. The intermediate plate includes a plurality of ridges and troughs, defining at least one intermediate plate peak and at least one intermediate plate valley. One or more of a pitch between adjacent intermediate plate peaks differs from a pitch between adjacent main plate peaks or an amplitude between adjacent intermediate plate peaks and intermediate plate valleys differs from an amplitude between adjacent main plate peaks and main plate valleys.

Additionally or alternatively, in this or other embodiments the pitch between adjacent intermediate plate peaks is greater than a pitch between adjacent main plate peaks.

The plate heat exchanger of claim 15 or 16, wherein the amplitude between adjacent intermediate plate peaks and intermediate plate valleys is greater than an amplitude between adjacent main plate peaks and main plate valleys.

Additionally or alternatively, in this or other embodiments one or more surface enhancements are located at the intermediate plate to induce vortices in the second fluid.

Additionally or alternatively, in this or other embodiments the one or more surface enhancements are one or more of material deformation at the intermediate plate or material removal from the intermediate plate.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the present disclosure, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a partially exploded view of an embodiment of a plate heat exchanger;

FIG. 2 is a schematic view of a plate arrangement in an embodiment of a plate heat exchanger;

FIG. 3 is a schematic view of a plate arrangement in another embodiment of a plate heat exchanger;

FIG. 4 is a schematic view of a plate arrangement in yet another embodiment of a plate heat exchanger; and

FIG. 5 is a schematic view of an embodiment of an intermediate plate for a plate heat exchanger.

The detailed description explains embodiments of the present disclosure, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION

Symmetric PHEs or BPHEs are constructed such that the first flow path and the second flow path have equal flow areas for the two fluids. The symmetric construction, however, can lead to a mass flux of one or both fluids through the heat exchanger which is not optimal. For example, a mass flux of the refrigerant through the first flow path may be lower than desired, while additionally or alternatively, a mass flux of the water or brine through the second flow path may be greater than desired. As a result, refrigerant-side heat transfer underperforms, and liquid-side pressure drop can be too high, thus limiting capacity of a heat exchanger of a given size. In an attempt to correct the mass flow differences, some PHEs and BPHEs are constructed asymmetrically, with different flow areas for the two fluids. Asymmetric PHEs and BPHEs have limitations as well, however.

Referring now to FIG. 1, illustrated is a partially exploded view of a plate heat exchanger 10. The plate heat exchanger 10 includes main plates 12, having ridged regions 14 and openings 16 corresponding to inlets and outlets of a fluid. The ridged regions 14 of the main plates 12 may have a herringbone, chevron or other suitable pattern to increase a surface area of the main plate 12 contacted by the fluid and to generate turbulence in the fluid. Adjacent main plates 12 are typically joined by, for example, brazing, welding, or adhesive bonding to define cavities between adjacent main plates 12 for fluid flow therethrough. The openings 16 of the main plates 12 may be provided, alternatingly, with protrusions or recesses surrounding the openings 16 to alternate a fluid that enters the cavities defined between adjacent main plates 12. For example a first fluid may enter first, third and fifth cavities between main plates 12, and a second fluid may enter second, fourth and sixth cavities between main plates 12. The fluids are maintained separate and exchange thermal energy as the fluids flow through the cavities.

The plate heat exchanger 10 includes a first end plate 18 at a first end 20 of the plate heat exchanger 10 and a second end plate 22 located at a second end 24 of the plate heat exchanger 10, opposite the first end 20. The first end plate 18 and/or the second end plate 22 includes end plate openings 26 substantially aligned with the openings 16 in the main plates to receive fluid fittings 28, 30, 32, 34 for entry of first fluid 36 and second fluid 38 into the plate heat exchanger 10, and for exit of first fluid 36 and second fluid 38 from the plate heat exchanger 10. For example, first fluid 36 may be input into the heat exchanger 10 via fitting 28 and output from the heat exchanger 10 via fitting 30, and second fluid 38 may be input into the heat exchanger 10 via fitting 32 and output from the heat exchanger 10 via fitting 34. While main plates 12 are shown having a rectangular shape in FIG. 1, it is to be appreciated that main plates 12 having other shapes may be utilized. For example, main plates 12 may have other rectangular, square, oval or any polygonal shape. Further, openings 16 and 26 may have a circular shape, oval shape, square shape, or any other desired cross-sectional shape. Embodiments are not limited to those illustrated, but include heat exchangers 10 having any desired shape.

Referring now to FIG. 2, a cross-sectional view of heat exchanger 10 is illustrated. The main plates 12 are layered such that first cavities 40 carry first fluid 36 and second cavities 42 carry second fluid 38. In some embodiments, the first fluid 36 is a refrigerant, and the second fluid 38 is water or a brine solution. The first cavity 40 and the second cavity 42 are defined between adjacent main plates, which as shown in FIG. 2, may have a plurality of peaks 44 and valleys 46. In some embodiments, the main plates 12 may be sinusoidal and have a main plate period 48 between adjacent peaks 44, and a main plate amplitude 50 between an adjacent peak 44 and valley 46. In some embodiments, a peak 44 of a first main plate 12 may contact or be secured to a valley 46 of an adjacent main plate 12.

At at least one portion of the heat exchanger 10, an intermediate plate 52 is positioned between two adjacent main plates 12, such that the intermediate plate 52 divides one of the first cavities 40 or, as shown in FIG. 2, one of the second cavities 42, such that the same fluid, either first fluid 36 or second fluid 38 flows on both sides of the intermediate plate 52 in cavity 42 a and 42 b. The intermediate plate 52 is configured to enhance thermal energy transfer between the first fluid 36 and the second fluid 38 in the heat exchanger 10. The second fluid can be directed across both sides of the intermediate plate 52 in the same flow direction, such as splitting the second flow 36 into two adjacent parallel flow paths a first in cavity 42 a, and a second in cavity 42 b. Further, the flow directions of the second fluid 38 in cavity 42 a may be different from a flow direction of the second fluid 38 in cavity 42 b. In some embodiments, these flow directions may be substantially opposite.

In some embodiments, such as is shown in FIG. 2, the intermediate plate 52 has a sinusoidal shape with a plurality of intermediate plate peaks 54 and intermediate plate valleys 56. The intermediate plate peaks 54 and intermediate plate valleys 56 define an intermediate plate period 58 between adjacent intermediate plate peaks 54, and an intermediate plate amplitude 60 between an adjacent intermediate plate peak 54 and intermediate plate valley 56. In some embodiments, the intermediate plate period 58 may be greater than the main plate period 48, or alternatively less than the main plate period 48, as shown in FIG. 3. Further, the intermediate plate amplitude 60 may differ from the main plate amplitude 50. For example, the intermediate plate amplitude 60 may be greater than the main plate amplitude 50 as shown in FIG. 2, or alternatively the intermediate plate amplitude 60 may be less than the main plate amplitude 50 as shown in FIG. 3. While the increases or decreases in period and amplitude are coupled in the embodiments of FIGS. 2 and 3, it is to be appreciated that in other embodiments, one or both of amplitude and period may be changed independently from the other.

Further, while in the embodiments of FIGS. 2 and 3, the intermediate plate 52 is disposed in a second cavity 42, in other embodiments the intermediate plate 52 is positioned in a first cavity 40, while in still other embodiments such as shown in FIG. 4, intermediate plates 52 are positioned in both the first cavity 40 and second cavity.

Referring now to FIG. 5, the intermediate plate 52 may include one or more enhancement features to improve thermal energy transfer and/or flow of the second fluid 38 through the second cavity 42. The enhancement features may include turbulators 62 formed in the intermediate plate by removal of and/or deformation of material of the intermediate plate 52. As shown, the turbulators 62 may take any of several shapes, including triangular, rectangular, circular or the like. Additionally, the turbulators 62 may take the form of tabs or perforations. Further, the enhancement features may be at least partially configured to be through holes in the intermediate plate 52. The enhancement features are generally configured to generate vortices to enhance thermal energy transfer between the first fluid 36 and the second fluid 38. Additionally, the intermediate plate 52 may have a thickness less than a main plate 12 thickness, as there is no pressure differential across the intermediate plate 52 since the same fluid is flowing on each side of the intermediate plate 52. While the intermediate plate is described herein as being located in the second cavity 42 with second fluid 38 flowing on both sides of the intermediate plate 52, it is to be appreciated that in some embodiments the intermediate plate 52 is located in the first cavity 40 with first fluid 36 flowing along both sides of the intermediate plate 52.

The heat exchanger 10 described herein with intermediate plate 52 increases thermal energy transfer in the heat exchanger 10 as compared to heat exchangers without the intermediate plate. As a result, refrigerant charge may be reduced and material usage reduced to achieve the same cooling capacity.

While the disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the disclosure is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the disclosure. Additionally, while various embodiments of the disclosure have been described, it is to be understood that aspects of the disclosure may include only some of the described embodiments. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. 

What is claimed is:
 1. A plate heat exchanger comprising: a plurality of main plates stacked to define a first cavity to direct a first fluid therethrough and a second cavity to direct a second fluid therethrough, the second fluid different from and kept separated from the first fluid; and an intermediate plate located in the second cavity between adjacent main plates, the second fluid directed across both sides of the intermediate plate.
 2. The plate heat exchanger of claim 1, further comprising one or more surface enhancements disposed at the intermediate plate to induce vortices in the second fluid.
 3. The plate heat exchanger of claim 2, wherein the one or more surface enhancements are one or more of material deformation at the intermediate plate or material removal from the intermediate plate.
 4. The plate heat exchanger of claim 1, wherein the main plates include a plurality of ridges and troughs, defining at least one main plate peak and at least one main plate valley.
 5. The plate heat exchanger of claim 4, wherein the intermediate plate includes a plurality of ridges and troughs, defining at least one intermediate plate peak and at least one intermediate plate valley.
 6. The plate heat exchanger of claim 5, wherein a pitch between adjacent intermediate plate peaks differs from a pitch between adjacent main plate peaks.
 7. The plate heat exchanger of claim 6, wherein the pitch between adjacent intermediate plate peaks is greater than a pitch between adjacent main plate peaks.
 8. The plate heat exchanger of claim 6, wherein the pitch between adjacent intermediate plate peaks is greater than a pitch between adjacent main plate peaks.
 9. The plate heat exchanger of claim 4, wherein an amplitude between adjacent intermediate plate peaks and intermediate plate valleys differs from an amplitude between adjacent main plate peaks and main plate valleys.
 10. The plate heat exchanger of claim 9, wherein the amplitude between adjacent intermediate plate peaks and intermediate plate valleys is greater than an amplitude between adjacent main plate peaks and main plate valleys.
 11. The plate heat exchanger of claim 9, wherein the amplitude between adjacent intermediate plate peaks and intermediate plate valleys is less than an amplitude between adjacent main plate peaks and main plate valleys.
 12. The plate heat exchanger of claim 1, further comprising a second intermediate plate disposed in the first cavity.
 13. The plate heat exchanger of claim 1, wherein a first flow direction of the second fluid at a first side of the intermediate plate is the same as a second flow direction of the second fluid at a second side of the intermediate plate.
 14. The plate heat exchanger of claim 1, wherein a first flow direction of the second fluid at a first side of the intermediate plate is different from a second flow direction of the second fluid at a second side of the intermediate plate.
 15. A plate heat exchanger comprising: a plurality of main plates stacked to define a first cavity to direct a first fluid therethrough and a second cavity to direct a second fluid therethrough, the second fluid different from and kept separated from the first fluid, each main plate of the plurality of main plates including a plurality of ridges and troughs, defining at least one main plate peak and at least one main plate valley; and an intermediate plate located in the second cavity between adjacent main plates, the intermediate plate including a plurality of ridges and troughs, defining at least one intermediate plate peak and at least one intermediate plate valley; wherein one or more of a pitch between adjacent intermediate plate peaks differs from a pitch between adjacent main plate peaks or an amplitude between adjacent intermediate plate peaks and intermediate plate valleys differs from an amplitude between adjacent main plate peaks and main plate valleys.
 16. The plate heat exchanger of claim 15, wherein the pitch between adjacent intermediate plate peaks is greater than a pitch between adjacent main plate peaks.
 17. The plate heat exchanger of claim 15, wherein the amplitude between adjacent intermediate plate peaks and intermediate plate valleys is greater than an amplitude between adjacent main plate peaks and main plate valleys.
 18. The plate heat exchanger of claim 15, further comprising one or more surface enhancements disposed at the intermediate plate to induce vortices in the second fluid.
 19. The plate heat exchanger of claim 18, wherein the one or more surface enhancements are one or more of material deformation at the intermediate plate or material removal from the intermediate plate. 